Steam still



Nov. 1, 1955 S. A. BLUNDELL, JR., ETAL STEAM STILL Filed Oct. 24, 1952 gmlllli FIG.4. 4

INVENTORS. SOLON A. BLUNDELL,JR. EUGENE H. FLEWELLEN,JR.

ATTORNEYS v United States Patent 1 2,722,507 STEAM STILL Solon A. Blundell, Jr., Pampa, and Eugene H. Flewellen,

Jr., Corpus Christi, Tex., assignors to Celanese Corporation of America, New York, N. Y., a corporation of Delaware Application October 24, 1952, Serial No. 316,589 2 Claims. (Cl. 202-234) This invention relates to a continuous still and relates more particularly to an apparatus for the continuous steam distillation of polymer slurries.

It is an object of this invention to provide a novel and efiicient still.

A further object of this invention is the provision of a new and improved apparatus which is particularly suitable for the continuous steam distillation of a polymer slurry.

Other objects of this invention will appear from the following detailed description and the accompanying drawmgs.

In the drawings, wherein a preferred embodiment of this invention is shown,

Fig. 1 is a plan view of the continuous still of this invention,

Fig. 2 is an elevation, partly in section, of the still,

Fig. 3 is an elevation, in section, taken along the line 3-3 of Fig. 2,

Fig. 4 is a sectional plan view of a portion of the still, with portions omitted and with arrows indicating the direction of liquid flow, taken along the line 44 of Fig. 2,

Fig. 5 is a sectional plan view of another portion of the still, with arrows indicating the direction of liquid flow, taken along the line 5--5 of Fig. 2,

Fig. 6 is a sectional elevational view illustrating the arrangement of air pipes and bafiies, taken along the line 66 of Fig. 4,

Fig. 7 is a sectional elevational view, illustrating the position of the holes in the steam pipes, taken along the line 7-7 of Fig. 5.

In the drawings reference numeral 11 is used to designate generally a still of rectangular shape, which is provided with end walls 12 and 13, side walls 14 and 16, a top 17 and a bottom 18. Process liquid which is to be steam distilled is introduced, preferably in a heated condition, through inlet valve 19 and inlet pipe 21 and through end wall 12 into the bottom of still 11. The pro cess liquid, which may be a thick slurry, fills the bottom half of still 11 to a level indicated by reference numeral 22 in Fig. 2; flows continuously through the still; and is removed continuously therefrom through exit pipe 23, which is provided with valve 24. In order to make the liquid passing through the still 11 follow a tortuous path, two sets of alternating baffles 26 and 27 are provided. Bafiies 26 are attached to side wall 14 and bottom wall 18 and extend across the still from side wall 14 almost to the opposite side wall 16. Bafiles 27, attached to side wall 16 and bottom wall 18, alternate with bafiies 26 and extend across the still from side wall 16 almost to the opposite side wall 14. The tops of all of the baffles 26 and 27 extend well above the liquid level 22. It is evident that the bafiles divide the liquid zone of the still 11 into a plurality of almost separate compartments 28, through which the liquid flows along the length of the still 11 and from side to side, as illustrated by the arrows in Figs. 4 and 5.

Steam is led into the bottom of still 11 through valve 29, steam pipe 31 and sparge pipe 32, which extends almost the whole length of the still 11 centrally thereof and passes through the lower portions of each of the baflles 26 and 27. The sparge pipe 32 is provided with several sets of holes 33, one set in each compartment 28, with alternating sets being on opposite sides of the pipe 32 and so arranged 2,722,507 Patented Nov. 1, 1955 that steam is projected out from each set of holes 33 in a direction which is horizontal and counter-current to the side-to-side flow of liquid in each compartment 28. The steam bubbles up through each compartment carrying with it the steam distillable portion of the liquid and then passes into the vapor space 34, above the tops of baflles26 and 27, and out of the still 11 through a dome 36 and vapor outlet pipe 37 to a condenser (not shown). To remove any entrained liquid from the vapors, the dome 36 is provided with baffles 38 and 39.

The accumulation of foam on top of the process liquid in the still 11 interferes with eflicient operation. To break up the foam the still 11 is provided with means for introducing blasts of air. Air is led in from a source pipe 44 into two lead pipes 46 and 47 which are connected by means of couplings 48 and 49 to two parallel pipes 51 and 52 which rest on top of the baflles 26 and 27. Each of pipes 51 and 52 has several spaced sets of air holes 53 and 54 so arranged that above any one compartment 28 there is one set of air holes directing a blast of air at an angle which is downward and countercurrent to the side-to-side flow of the process liquid in that compartment. That is, the downward blasts of air have horizontal components which are counter-current to the horizontal components of the liquid flow.

The pipes 51 and 52 may be rotated individually in the couplings 48 and 49 to vary the downward angle of the air blast; a 45 angle, as shown in Fig. 6, is preferred.

The still described above has been used very successfully, in the production of filament-forming polyurethanes, to remove the toluene from a thick slurry of particles of polyurethane in a medium comprising an emulsion of toluene in water.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention what we desire to secure by Letters Patent is: I

1. A steam still comprising a substantially rectangular vesesl having a liquid inlet at one end and a liquid outlet at the opposite end, a plurality of vertical bafiles extending across the vessel from each side thereof almost to the other side, said vertical baflles being arranged so that alternate bafiies extend from opposite sides to provide a plurality of connected compartments through which the liquid flows in a tortuous path from said inlet to said outlet, the tops of said batfies being above the liquid level and below the top of the vessel, a steam pipe extending transversely through said baflies near the bottom of the vessel and having apertures below the surface of the liquid in said compartments, the apertures being on opposite sides of said pipe in adjacent compartments and so arranged that substantially all of the steam is introduced into the liquid in a direction counter-current to the liquid flow in each compartment, and means for removing gaseous distillation products from said vessel.

2. A steam still as set forth in claim 1, in which a plurality of air pipes extend transversely of said bafiles and above said bafiies, said air pipes having apertures facing downward and counter-current to the flow of liquid for directing blasts of air at the surface of the liquid in said compartments.

References Cited in the file of this patent UNITED STATES PATENTS 524,704 Chesebrough Aug. 21, 1894 1,041,082 Hird Oct. 15, 1912 1,317,688 Davenport Oct. 7, 1919 1,433,052 Wells Oct. 24, 1922 1,443,528 Dunham Jan. 30, 1923 1,913,882 Hills June 13, 1933 1,924,919 Flowers Aug. 29, 1933 

1. A STEAM STILL COMPRISING A SUBSTANTIALLY RECTANGULAR VESSEL HAVING A LIQUID INLET AT ONE END AND A LIQUID OUTLET AT THE OPPOSITE END, A PLURALITY OF VERTICAL BAFFLES EXTENDING ACROSS THE VESSEL FROM EACH SIDE THEREOF ALMOST TO THE OTHER SIDE, SAID VERTICAL BAFFLES BEING ARRANGED SO THAT ALTERNATE BAFFLES EXTEND FROM OPPOSITE SIDES TO PROVIDE A PLURALITY OF CONNECTED COMPARTMENTS THROUGH WHICH THE LIQUID FLOWS IN A TORTUOUS PATH FROM SAID INLET TO SAID OUTLET, THE TOPS OF SAID BAFFLES BEING ABOVE THE LIQUID LEVEL AND BELOW THE TOP OF THE VESSEL, A STEAM PIPE EXTENDING TRANSVERSELY THROUGH SAID BAFFLES NEAR THE BOTTOM OF THE VESSEL AND HAVING APERTURES BELOW THE SURFACE OF THE LIQUID IN SAID COMPARTMENTS, THE APERTURS BEING ON OPPOSITE SIDES OF SAID PIPE IN ADJACENT COMPARTMENTS AND SO ARRANGED THAT SUBSTANTIALLY ALL OF THE STEAM IS INTRODUCED INTO THE LIQUID IN A DIRECTION COUNTER-CURRENT TO THE LIQUID FLOW IN EACH COMPARTMENT, AND MEANS FOR REMOVING GASEOUS DISTILLATION PRODUCTS FROM SAID VESSEL. 